Pain,muscle spasms and twitching fingers following brachial plexus avulsion

Three patients who, following partial brachial plexus avulsion, experienced pain, involuntary finger twitching and muscular spasms are reported. Two exhibited cutaneous trigger zones, stimulation of which exacerbated their pain; changes in emotional tone aggravated both the pain and the spasms. Pain would appear to be due not only to deafferentation and scarring of the dorsal horn, but also to an afferent pathological barrage from partially damaged dorsal roots. The pathological sensory barrage may activate metameric interneuronal circuits and produce involuntary movements. Exacerbation of both the pain and the spasms can be explained on the basis of intrinsic properties of these ectopic pacemakers.